The lifetime prevalence of abdominal aortic aneurysms among siblings of aneurysm patients is eightfold higher than among siblings of spouses: An analysis of 187 aneurysm families in Nova Scotia, Canada

Background: Abdominal aortic aneurysms (AAAs) are frequently familial. The aim of this study was to compare the prevalence of AAA among the siblings of AAA patients with that in the spouses' siblings. Methods: The siblings of 375 AAA patients and the siblings of the spouses of the AAA patients were included in this study and offered ultrasonography screening for AAA. Participants were asked to complete a questionnaire to collect demographic and general health information. Statistical analysis was done with Fisher's exact test. Odds ratios and 95% confidence intervals were also calculated. Results: Abdominal ultrasonography examinations were done for 309 individuals. The results indicated that 11 (11.2%) of 98 brothers of AAA patients, 4 (2.7%) of 147 sisters, and none of the 64 siblings of the spouses of the AAA patients were found to have an AAA. Combining the information from the ultrasonography screening and medical records on already known cases of AAA in these families, altogether 29.0% (44/152) of the brothers of AAA patients, 11.1% (20/181) of the sisters of AAA patients, and 2.3% (2/88) of the siblings of the spouses had an AAA. Conclusion: There was a significant difference between the siblings of the AAA patients and those of the spouses both in the frequency of AAA detected by ultrasonography screening and in the overall prevalence of AAA. The overall prevalence of AAA in the siblings of AAA patients was about eight times that observed among the siblings of their spouses (19.2% vs 2.3%). These findings confirmed previous reports on high prevalence of AAA among siblings of AAA patients and emphasized the importance of an ultrasonography screening program for siblings of AAA patients.